Process of subjecting materials to the action of air or other gases.



J. E. GREENAWALTL- PROCESS 0F SUBJEGTING MATERIALS TO THE AGTIQNOEAIR 0R OTHER GASES. i

APBLICATIONHLED mmm-1904.

@HMG/#wo v v J. E. GREENAWA'LT. l PRQGQSS OF'SUBJEGTINGMAIERIALS To THB ACTION 0F AIRWOR OTHER GASES.

APPLIUATIQN FILED JAN. ze',

M04. Patented May.' -1 1, 1909.v

3 sHEBTs-sHEET 2.

Wmme@ J. l'15.*'GmlamWALT. PROCESS O I SUBJECTING MATERIALS TO THE ACTION 0E AIR OR OTHER GASES.

APPLICATION FILED JAN.2`G, 1904.

Patented May 11, 1909.

3 SHEETS-SHEET 3.

f f1/wanton UnrrEn sfra'rEs PaJrEnr OEEioE;

JOHN EOKEET GEEENAWALT, or DENVER, COLORADO.

PnocEss oF sUBJEcTING MATERIALS rro THE Ac'rIoN 0F AIR on OTHER GASES.

Specification of Letters Patent.

Patented May 11, loco.

Original application filed December 27, 1901, Serial No. 87,510. Divided and this application led January 26, 1904.

Serial No, 190,726.

To all whom it may concern:

Be it known that I, JOHN E. GREENAWALT, a citizen of the United States of America, residing in the city and county of Denver and State of Colorado, have invented certain newl and useful Improvements in Processes of Subjecting Materialsto the Action of Air or other Gases; and I do declare the following to be aA full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to Ythe accompanying drawings,` and to the figures of reference marked thereon, which form a part of this specification. u

y invention relates generally to a process of treating materials by subjecting them -to the action of gas and more specifically to an oxidizing process in which air or other gases are afvantageously introduced to the 1 materials by forcing the air or gas or both from below up through a porous hearth vor bed directly into the material lying on' the bed or hearth above.

In .this specification my process will be described as applied to the oxidation or lroasting of ores in order to free the ore from those elements which render it refractory and prevent their successful and economical treatment when in the raw or natural state in which they are taken from the mines.

My Objectis to eliminate the mechanical K and metallurgical difiiculties encountered in the preparation of gold, silver and copper ores for the extraction of -the values by a chemical solution. A,

Thisa plication is divided out of an application ed by me-Dec. 27th, 1901,` Serial No. 87,510, entitled improvements in roasting furnaces which lastnamed a plication lwas divided out of an t plication t ed byme Oct. 12th, 1901,Seria1 do. 78,481.' The roasting operation forms a very important factor'in the successful extraction of the precious metals from their ores by means of a.

chemical solution; the object sought being to leave the precious metals in a condition to bev acted upon by the solvent and toput the rbasermetals and elementsin acondition to resist the action of the solvent. To do this properlyrequires an abuhd ant supply of oxygen in order to thoroughly oxidize altthe oxidizable elements before subjecting the ore to the high temperature required vby some of the base elements to resist the gold dissolving solution.

The principal diiiiculties encountered in the oxidizing of ores as heretofore racticed are encountered in connection wit 1 the airVV supply. In the roasting processes ashereto:Y fore practiced in reverberatory furnaces, except in connection ,with the furnaces built under my supervision for the carrying out of` the process herein set forth, the onlyrnea'ns.-

ofsupplying air is at the upper surface of the 6 ore and this is so slow and imperfect that the ore is generally moved into the highly heated region of the furnace before all the combustible elements'havebeen oxidized; the result is that some of the mineral, particles become cindered and fused, thus preventing a high percentage of .extraction of the gold and silver. I have determined that all of the combustible Aelements of the ore can be burned or oxidized at a comparatively low temperature when the ore is supplied with an abundance of pureair, and that the oxidized mineral particles are left open and porous; also, that the capacity of the furnace is largely increased.y

The invention will now be described in detail reference being made to the accompanying drawing which illustrates a suitable apparatus for carrying out or practicing my invention.

Figure 1 represents a cross section of the furnace. Fi 2 is a section taken lengthwise of the urnace, the parts being shown on a smaller scalel Fig. 3 shows an important modification of the apparatus. y

In Fig. 1 ofthe drawing is shown the method of introducing the air tothe ore through the porous hearth, also the manner of cooling the rabble tracks. In the construction of this furnace prefer to build ka 95 lcement for a finished coating, leaving a space of about nineinclies between this hearth proper and the lowest point of the rabble plows. This space, which extends almost theentire length of the furnace, I divide into sections approximatelv square by solid Walls reaching'nearly to the lowest tions is necessary to control the amount of f ieces above them and so on until the lastsoA . regular intervals.

air delivered to the orep'atth'e various stages l of the roasting operatlon. A t the side 'of the furnace I arrange a large conduit5 leading to the center of each section.- The ob.-

ject of this conduit is to make the'interior of the 4furnace accessible for re airs, etc, In`

the s ace between' the heart and the rabblesv b'uild what I prefer to. call aporous filter 8 consisting of large ieces of ore at the v bottom and in 'thecon uit, with smaller our inches which consists of ore as fine as that which is to be roasted and from which the intenselyfine dust has been screened. Upon this filter the ore rests in its passage through the furnace, the rabbles passing over the filter yand n iovingthe .ore aheadjat The ai1 and steam, when it is desirable to u'sejsteam in the roasting operation are passed under pressure from the main pipes 9 and 1-7 to a branch -pipe y10 into the conduit 5 of each section and thence tol the hearth. The large spaces among the coarse orehperiuit the aiuto quickly and evenly distribute itself over the hearth and then filter or percolate uniformly through the interstices b'etwee'nthe fine ore-particles; the idea bein r not to-create ablast of air, but to simplyiave a light pressure and force the air through thepores ofthe filter without disturbing the porous filter or the ore particles. The action is analogous to watery percolating through ore 'placed on a sand filter. l` This construction can alsok be used to introduce chlorin or. other 'gaseous prod-q ucts into the ore mass' d uring its passage through the furnace. While I preferore .for

'the construction of this filter, it is evident that any suitable line porous material, suchV as fine sand, mineral' wool, fibrous asbestos,

ete., supportin the weight of the ore inits passage throur the furnace, with means to conduct `air tirough -itinto .the ore massf would answer the purpose.- However, `low recious metals find their way into the filter,

1t canbe removed and given the regularv treatment for the v,extraction of whatever values it may contain. u l 1,. i The tracks 14 uponV which :the wheels \13 ofthe rabbles run, are madeof hollow cast iron, the interior of which 4is sealed from the furnace, and arranged for cooling either by air or Water, preferabl" by water indirectly by placing a pipe 15 filled with Water into it.` This water pipe', will hollow cast iron track also has a -flange 14a to receive the tile partition 16 separating the ore from the track, so that the tile can Abe bolted to the track, so that it will always 'retain its position relatively to the track.

. In Fig. l2 are shown the sprocket'wheels 21 yand -27over 4which the chains and rabbles travehand also the track 22 above the furnace Where the rabbles and chains are cooled von their return journe This section also shows theporous heart and the walls 23 dividing the.'porous hearth into sections, so that varying quantities ol' the air can be do- `live-red` tothe `ore, massduring its travel throughtlie furnace. i Y

i The feeding of the ore to the furnace hearth I accomplish as follows: 'In the ore b in 24,' I place an adjustable gate 25 which canbe raised or lowered, thus raising or lowering the surface ofjthe-orevmass as it comes frein the bin. The ore in the bin being fine and perfectly 'dry' always assumes approximately the same angle, and by raising or lowering the gates, the rabbles cut into theol-e to a greater or less extent and consequently` the amount of ore fed into the furnace can be varied as desired. The's'haft' 26 carrying the rear sprocket wheels 2 7 is mounted' on adjustable take-up boxes the adjustment being effected by screws 28. "lhe chains used ordinarily for-this purpose i are quite heavy and there 1s considerable sag.

in the chain between ,the rabbles, so that'the l lshaft. 26 can benioved backward vorforward considerably without interfering with the operation of the chain or rabbles; consequently by ineansof the screws 28' the rabbles can be made to cut into the ore to av greateror less extent and the -amountof ore fedginto ,the'furnace governed accordingly.

" I (prefer to heatthe furnace with. producer gas whichI introduce at '29 (see Fig. 2) per-- mitting it to flow over thehot roasted ore before it is withdrawn from the pit orhopper 4 .30. .Itpas'ses through the opening 31 into the, furnaeejv :"l'g. 3 show s a tracklt constructed with its interior exposed to .the atmosphere so that A itis acceSSib e from"fthe'--outslc'lel It also shows the mannerof constructing the'porous hearth forl hand-furnaces'where'hoes or `hand rake's are'f'u'sfed to stir the ore.` Inv this case Athere,Iisahspace of about one inchleft between the `bricks ofl-thehearth and this,

12o aqis filled with oro'us material and sup-v A t the introduction of the `brick'diminishes, the porousA area considerably,.yet it isfnecessary 1n order to pro-` tect the porous material from1 the hoe or rake ofthe workmen in hand furnaces Having claim is:

thus described in y invention,what l I 1. The process ofloxirlizi ore, which con-` then'subjeotin the sulfiids fao-.heat nclforc- Y. sists in placing the ore on al' ed composed` of in`g airupwar `y tluough the bed; K 10 substance which is naturali porous, sub- In testimony whereof I ',aflx my signature jetng the ore to heat, and t en forcing air in presence of two Witnesses.

5v upwardly through the b ed and intothe ore. JOHN ECKERT GREENAWALT.

2. The process of roestingore suhids,` Witnesses: which consists in placing the sulds on -af JOHN L. GRETHER; porous bed of loose granular material, and F. J. KO'TSREAU. 

